Safety device for hoists



1,558,955 c. R. WELCH SAFETY DEvlcE Foa Hols'rs Oct. 27, 1925.

Filed May 10. 1924 nveno@ Clare/:ce i?. Melk/2.

oFF Posmn/v Co/YrRaLLER Patented Cet. 27, 1925.

UNITEDSTATES PATENT OFFICE. l`

CLARENCE R. WELCH, F DENVER, COLORADO.k

SAFETY DEVICE FOR HOISTS.

l able others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, and to thccharacters of reference marked thereon, which form appart of thisspecication.

This invention relates to safety devices for hoists, and has referencemore particularly to a system adapted to be used in connection with minehoists.

In mines and in other places where similar conditions prevail, materialis hoisted from the mine to the surface. The hoist is operated either bySteam or by electric energy. In either case the machinery is located atthe surface and is under the controlof an attendant. The hoist cagetravels between an upper and a lower landing. As a rule it is loadedwhile at the bottom and unloaded at the top. There areseveral'conditions essential to safety. First, the cage must he stoppedat the proper position at both landings. second, the attendant must beprevented from starting the hoist before the cage is properly loaded andunloaded and.l

third, the engineer must not start the hoist in the wrong direction. Insome places, automatic controllers are installed, which Astop themachinery when the cage has reached the limitof travel in eitherdirection, while in other places the entire re# sponsibility rests uponthe attendant or engineer.

In cases where automatic controllers are not employed, the engineer isgoverned in his actions by an indicator that shows kthe position of thecage ateach instance. Such indicators are usually very simpleand comeprise a dia-l or a pointer that is rotated'from the hoisting drum. j if.

It is the object of this invention to pro-l duce Va safety device whichwillfautomatically lock the controller lever in 'neutral position at theend of each travel of the hoist, as well'asto put an obstruction inthetherewith.

Appuation mea May 1o, 1924'. serial No. 712,497.

way of the reversing lever to prevent the latter from being moved 1n thewrong direction. Means is also provided whereby the loaderat the bottomor the unloader at the top can vrelease the controller and thereversinglever whenever .the cage is ready' to travel.

In order to explain my invention with the greatest degree of clearness,I shall have reference tothe accompanying drawing in which the same isshown diagrammatically.

yNumeral 1 designates a controller lever that is pivoted at 2 and has arod 3 extends ing .to the throttle valve of an engine or thecontroller'of a motor as the case may be. Numeral 4 represents areversing lever which, for the purpose of illustration, is

shown pivoted at 5 and has attached to it a.

rod 6 that extends to and controls the reversing gear, if a steam engineis employed, or a reversing switch in case a motor is employed. Numeral7 represents an indicator dial that is lconnected to the hoisting drumby means which cause it to rotate in unison The direction of rotationfor the up and the down travel of the hoist is indicated by the arrows.yThe indicator dial is provided with holes 8 which serve to receive thepivot pins 9 of the pawls 10. A y

switch is located adjacent the dial 7 and 'is so constructed that it isoperated by the pawls 10. In the present instance the switch is showndiagrammatically as consisting of a vertical member pivoted intermediateits ends at 11 and whose upper end 12 projects upwardly into the pathvofthe pawls 10. Secured to the lower end 13 of the vertical member is arod 14e which extends through the open center of thesolenoid 15 and hasattached to it two collars 16 and 17 which are spaced apart such adistance that the distances between their outer faces 'is equal to orslightly less than the length of the solenoid. Circular armatures 18 areslid ably mounted on the rod 14 in the manner shown. The end of the rodis provided with a head 19. v

It is now apparent that if the rod 14 is moved `towards the right, therighthand armature will be moved to the dotted line position,

and when the magnet is energized, the armature and rod will be returnedto the full line position shown. If the rod 14 is moved towards theleft, the lefthand armatureA will he moved to the dotted line positionand Vwill, upon energization of the magnet, be

' rod 23. rhis springl tends to move'the armature away from the end ofthe magnet. The end of the rod 23 nearest the pivot 2 has a pawl 27pivoted thereto at 23. spring 291 imparts to the pawl a tendency torotate about the pivot 23 in a counter-clockwise direction. Then themagnet 22 is energized, the pawl 2l" engages the edge of part 20 andwhen the controller handle moves to olil position, it engages the notch21 in the manner shown on the drawing` and prevents the controller frombeing moved into running position while the solenoid 22 is energized.

VOn each vside of the reversing lever 4, l have shown solenoid magnets29 and 30. Each magnet has a cylindrical armature or core 31 whose axescoincide with the plane ot movement of the reversing lever. When thearmatures are retracted 'in the manner shown in the drawing, thereversing lever can be moved freely trom up7 to down position and b cliagain. lit, however, one

' of the magnets 29 or 30 lare energized, the

core will be projected towards the reversing handle and form a stepwhich will act as a safety device to prevent the engineer from movingthe lever to up position when the cages are atv the top or to downposition when the cage is at the bottoni.

l will now explain the manner in which the various parts that lhavedescribed are interconnected and how they cooperate lo produce theresults desired.v

The energy for operating the various magnets will he taken trom thepower supply available at the mines, but t'or the purpose ot thisexplanation l have shown a battery 32. One pole oi this battery isconnected to 'the solenoid 22 by means oi:` a wire 33.' A second wire 34extends from the other endot the solenoid coil to the terminals 35 and352%- From the other' pole oi" the battery a wire 136 extends to theterminals 36 and 36a.' vIt lis now apparentthat when contact is madebetween either pair oi contacts 351 36 or35a, 36a, the solenoid 22 willbe energized and' the ari'naturev 24 attracted and moved to 'theposition vshown in the drawing. v

A wire 37 connects one Vend oi the coils ot each of magnets 29 and 30with one pole of the battery 32." A'wire 33 extends from this 'same'battery terminal to theconta'cts y39 and A tension' 398. A. wire 40connects the other end of the winding of magnet 30 with the terminal 43,while a wiref42 connects the magnet 29 in a Similar manner with thecontact 41. rlhe switch member 12, 13 has secured thereto conductingportions 44 and 45 that are insulated 'I'rom each other and adapted,respectively, to vconnect contacts 39, 43 or 39a, 41 and contacts 35, 36or 35-36a when the switch occupies one or the other of the dotted linepositions.

Let us now assume that thehoist is traveling upwardly. The controllerlever 1 will occupy the running position; the reverse lever 4 will he inthe up position, andthe indicator disk will rotate in the direction ot'the arrow marked up. wWhen the engineer sees that the hoist vis near itsupper li'init'ot' travel he brings the controller handleto oft position.A short time before the hoist reaches the end of its travel, one of thelugs 10 will engage the arm 12 and rotate the switch membercounter-clockwise into dotted line position. This energizes the magnets22 and 29. The rod 23 is projected to the left into the position shownand at the same time the core armature 31 of magnet 29 is moved towardsthe lever 4. Since the arm 12 ot the switch moves about the pivot 11,its end travels in the are of a circle1 and since the pawls 10 alsotravel in a circular path which intersects the path o1E the end of arm12, it is evident that by properly spacing the parts` the pawls 10 willbe permitted to move the switch to closing position and then pass 'bythe end of arm 12 so that the latter' will he tree to be moved 'back toneutral position. it is for this purpose that the pawls 10 are pivotedat 9. When the cage has been unloaded, the switch Si is closed. Thisenergizes the solenoid 15 and brings the switch back to neutralpositionl 'lhis releases the controller handle and permits thelengineer' to start the hoist.A The magnets 29and 30 must` of course, bemade ot suflicient strength to move the reversing lever to neutralposition whenever either magnet or 3() is energized. When the hoist cageapproaches the lower level, the otherpawl 10 throws theswitch member inthe opposite direction, thereby energizing magnets 22 and 30. llVhen thecage is ready for the return trip, the switch 52 is closed'. Thisreleases the'control and reverse 'levers in the manner explained. Y

From the above, it will be apparent that I have devised a combination ofelements :operatively Vrelated to each other and' cooperating to producea safety device that will reduce to a minimum accidents due to thepremature starting olihoists'. As explained above, the control lever risautomatically locked in oil positionfwhen the hoist reaches the endotitsftravel in either direction. tThe reversing lever is automaticallyreturned to neutral position at the ends of the hoist travel and thehoist is thereby held against accidental stopping. Switches are providedat the top and bottom for releasing the looking means when the hoistcage is in con'- dition to be moved.

Having now described my invention, what Il claim as new is:

l. A hoist safety system comprising, in combination, a controller lever,an indicator adapted to move at a speed proportional to the speed of ahoist cage, an electromagnetic device operatively related to the controllever and adapted to lock the same in off position, means operated bythe yindicator for causing said electromagnetic device to function whenthe indicator passes a predetermined point, and manually operated meansfor restoring Said device to normal position.

2. A safety system for hoist control, comprising, in combination, anindicator adapted to move at a rate proportional to the rate of a hoistcage, a switch located adjacent the indicator, means on the indicatorfor moving said switch in one direction when the indicator passes apredetermined point in one direction, means on the indicator for movingsaid switch in the opposite direction when the indicator passes apredetermined point while moving in the other direction, a controllerhandle for stopping and starting said indicator, an electromagneticdevice operatively related to the controller, said device being adaptedwhen energized to lock the controller in ofi position, and meanscontrolled by the switch for rendering said device operative orinoperative.

3. A safety system for hoist control, cornprising, in combination, anindicator adapted to move at a rate proportional to the rate of a hoistcage, a switch located adjacent the indicator, means on the indicatorfor moving said switch in one direction when the indicator passes apredetermined point in one direction, means on the indicator for movingsaid switch in the opposite direction when the indicator passes apredetermined point while moving in the other direction, a controllerhandle for stopping and starting said indicator, an electromagneticdevice operatively related to the controller, said device being adaptedwhen energized to lock the controller in off position, means controlledby the switch for rendering said `device operative or inoperative, areversing lever, and electromagnetic means operatively related to' thelever and to the switch for mowing sai-d lever to neutral position whenthe switch operates.

4. A safety system for hoist control, coinprising, in combination, anindicator adapted to move at a rate proportional to the rate of a hoistcage, a switch located adjacent the indicator, means on the indicatorfor moving said switch in one direction when the indicator passes apredetermined point in one direction, means on the indicator for movingsaid switch in the opposite direction whenL the indicator passes apredetermined point while moving in the other direction, a controllerhandle for stopping and starting said indicator, an electromagneticdevice operatively related to the controller, said device being adaptedwhen energized to lock the controller in off position, means controlledby the switch for rendering said device operative or inoperative, areversing lever, electromagnetic means operatively related to the leverand to the vswitch for moving said lever to neutral position when theswitch operates, and electromagnetic means connected to the switch andadapted to move the same into inoperative position.

5. A safety system for hoist control, comprising, in combination, anindicator adapted to move at a rate proportional to the rate of a hoistcage, a switch located adjacent the indicator, means on the indicatorfor moving said switch in one direction when the in# dicator passes apredetermined point in one direction, means on the indicator for movingsaid switch in the opposite direction when the indicator passes apredetermined point while moving in the other direction, a controllerhandle for stopping and starting said indicator, an electromagneticdevice operatively related to the controller, said device beingadaptedwhenvenergized to lock the controller in oli` position, Ymeanscontrolled by the switch for rendering said device operative orinoperative, a reversing lever, electromagnetic means operativelyrelated to the A lever and to the switch for moving said lever toneutral position when the switch operates, and electromagnetic meansconnected to the switch and adapted -to move the same into inoperativeposition, and means for controlling said last-named means, said meanscomprising switches located at convenient points.

In testimony whereof I aiix my signature.

CLARENCE R. WELCH.

